Over the years many devices have been developed to prepare grain. In some cases export considerations dictate that the picked grain product (e.g., corn) be scalped to separate its parts that support the undesired portion from the desirable grain portion. For example, corn infested with the European Corn Borer Larva needs to be scalped before export to insure that the stalks, cobs and large refuse (usually over 1/2 inch in size) where the larva lives, are separated from the exportable residual grain. Presently such scalpers require U.S. Department of Agriculture (USDA) approval before they can be used and are designed to operate either by using a gravity feed, vibration, drag type, aeration or a combination thereof combined with a filtering screen. Most such units are limited to processing no more than 15,000 bushels per hour of corn. The present improved scalper invention differs from such earlier separation methods by combining a rotary sweep with a screen to provide the desired scalper operation at an increased speed (40,000 bushels per hour or more over a 1/2 inch screen) with a more reliable operation and less expensive installation and operating cost. This increase in reliability is attributed to the use of fewer moving parts to perform the scalper operation at a greater speed.